<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        #wrap {
            position: relative;
            height: 110px;
            width: 760px;
            margin: 50px auto;
            overflow: hidden;
            border: 1px solid red;
        }

        #content {
            height: 110px;
            position: absolute;
            list-style: none;
        }

        #content li {
            float: left;
        }
    </style>
</head>
<body>
<div id="wrap">
    <ul id="content" style="left: 0;width: 1520px;">
        <li><img src="img/1.jpg"></li>
        <li><img src="img/2.jpg"></li>
        <li><img src="img/3.jpg"></li>
        <li><img src="img/4.jpg"></li>
        <li><img src="img/1.jpg"></li>
        <li><img src="img/2.jpg"></li>
        <li><img src="img/3.jpg"></li>
        <li><img src="img/4.jpg"></li>
    </ul>
</div>
</body>
<script>
    var ul = document.getElementById("content");
    var maxWidth = parseInt(ul.style.width);
    var speed = 10;
    var timer = setInterval(function () {
        var left = parseInt(ul.style.left);
        if (left <= (-maxWidth / 2)) {
            ul.style.left = 0;
            left = 0;
        }
        ul.style.left = left - speed + "px";
    }, 100)
</script>
</html>